What Does US Support for South Korea's Nuclear Submarines Mean?

The South Korean government has confirmed a historic agreement with the United States to construct nuclear-powered submarines, a significant development in military cooperation amid rising tensions on the Korean Peninsula. This partnership aims to enhance South Korea's defence capabilities against North Korea's nuclear ambitions and expand its regional influence.

Last updated: 14 October 2023 (BST)

What’s happening now

The agreement between South Korea and the United States marks a pivotal shift in military dynamics in East Asia. This collaboration will see South Korea develop nuclear-powered attack submarines, a move approved by the US government, which is also providing assistance in sourcing nuclear fuel. The announcement comes at a time of heightened military activity in the region, particularly from North Korea, which has been aggressively pursuing its own nuclear submarine programme. This development is expected to bolster South Korea's defence posture and further complicate the strategic landscape in the region.

Key takeaways

South Korea has finalised a deal with the US to build nuclear-powered submarines.
The agreement is part of a broader military and economic partnership between the two nations.
North Korea's ongoing nuclear ambitions have prompted this strategic shift in South Korea.
China has expressed concerns about the implications of this deal on regional stability.
The submarines are seen as a critical enhancement to South Korea's military capabilities.

Timeline: how we got here

The agreement's development can be traced through several key milestones:

October 2022: Initial discussions between US and South Korean leaders regarding military cooperation.
September 2023: Announcement of a broader trade deal reducing tariffs on imports to 15%.
14 October 2023: Finalisation of the agreement for the construction of nuclear-powered submarines.

What’s new vs what’s known

New today/this week

The recent announcement solidifies a framework for South Korea to develop its own nuclear-powered submarines, with the United States agreeing to assist in the construction and supply of nuclear fuel. This marks the first time South Korea will enhance its naval capabilities to include nuclear propulsion.

What was already established

Previously, South Korea relied on diesel-powered submarines, which require more frequent surfacing and have limitations in operational range and speed. The country has a history of military cooperation with the US, particularly in response to North Korea's nuclear threats, but this agreement represents a significant upgrade in military technology.

Impact for the UK

Consumers and households

While the direct impact on UK consumers may be limited, the geopolitical shifts in East Asia could have broader implications for global security and trade, potentially affecting energy prices and international markets.

Businesses and jobs

The construction of nuclear submarines will likely lead to increased defence spending in South Korea, which may affect international relations and trade agreements. UK businesses involved in defence technology could see opportunities for collaboration or competition.

Policy and regulation

The UK government will need to monitor developments closely, particularly regarding the implications for defence policy in the Indo-Pacific region and its relationship with both South Korea and the US. Upcoming international summits may address these strategic shifts.

Numbers that matter

6: Total number of countries with nuclear-powered submarines (US, China, Russia, UK, France, India).
20: Current number of diesel-powered submarines in South Korea’s fleet.
£265 billion: South Korea's planned investment in the US as part of the trade agreement.
50: Estimated number of nuclear weapons in North Korea’s arsenal.
15%: Reduced tariff rate on exports from South Korea to the US.

Definitions and jargon buster

Nuclear-powered submarines: Submarines that use nuclear reactors to operate underwater for extended periods without surfacing.
Diesel-powered submarines: Submarines that rely on diesel engines, requiring them to surface more frequently for air.
Trade agreement: A pact between countries to facilitate trade and reduce tariffs.

How to think about the next steps

Near term (0–4 weeks)

South Korea will begin the process of adjusting its nuclear agreements with the US to facilitate the supply of nuclear fuel and establish military use protocols.

Medium term (1–6 months)

As construction plans develop, South Korea's defence budget may increase significantly, reflecting the need for enhanced military capabilities in response to North Korea's threats.

Signals to watch

Details on the timeline and location of submarine construction.
Reactions from North Korea and China regarding the agreement.
Future military exercises involving South Korea and the US.

Practical guidance

Do

Stay informed about developments in the Korean Peninsula.
Monitor changes in international relations and trade policies affecting the UK.
Engage with news sources for updates on military technology advancements.

Don’t

Underestimate the implications of military agreements on global security.
Ignore the potential economic effects of rising defence budgets.
Neglect the importance of diplomacy in mitigating tensions.

Checklist

Review the implications of the South Korea-US submarine deal on regional security.
Identify potential impacts on trade and economic relations with East Asia.
Evaluate the influence of military advancements on global power dynamics.
Consider how this agreement might affect UK defence policy and cooperation.
Stay updated on any changes in North Korea's military posture following this agreement.

Risks, caveats, and uncertainties

It's important to note that while the agreement enhances South Korea's military capabilities, it does not fundamentally alter the balance of power in the region. The costs associated with developing nuclear submarines are substantial, and questions remain about South Korea's ability to operate them effectively without its own nuclear weapons programme. Additionally, how North Korea and China will respond remains uncertain, with potential for increased tensions that could escalate conflicts.

Bottom line

The agreement between South Korea and the US to construct nuclear-powered submarines is a significant step in military collaboration, reflecting the changing dynamics on the Korean Peninsula. It underscores the importance of defence preparedness in the face of North Korea's nuclear threats while highlighting the delicate balance of power in East Asia. As developments unfold, it will be crucial for the UK and other nations to monitor the implications for regional and global security.

FAQs

What are nuclear-powered submarines?

Nuclear-powered submarines are military vessels that utilise nuclear reactors for propulsion, allowing them to operate underwater for extended periods without needing to surface frequently.

Why is South Korea building nuclear submarines?

South Korea is building nuclear submarines to enhance its defence capabilities against North Korea's growing nuclear threat and to strengthen its military position in East Asia.

What will be the impact of this agreement on regional stability?

The agreement may increase tensions in the region, particularly with North Korea and China, as it represents a significant escalation in military capabilities for South Korea.